arkansascontrols
Lifetime Supporting Member
Question for the FTV Gurus.
I have a recurring issue with SE applications that use shared displays. I have a workaround but I'd really like to find a cleaner method.
Here's the layout.
I have an HMI that provides data on multiple identical systems. The main display provides an overview of all systems. From the main display the detail screens can be loaded for whichever system the user chooses. I use the same detail displays with tag place holders and load the displays with a parameter file for each system. This works well. However I have always have one or more detail displays that contain an ActiveX Trend object. I have Trend Templates setup for each system.
The problem is I haven't found a clean way to pass a variable to the display that it can use to load the correct trend template.
Here's what I've done in the past that I'm hoping to improve upon.
I define a Memory Type tag for System_number. From the button that loads the display I set the value of the memory tag first, then load the display with a /pParameter_File. Then in the Display_Load Event (VBA) I define taggroup and tag and assign the tag value to a VBA variable and then use the methods of the Trend ActiveX to load the trend template I want. Sounds like a Kludge Huh?
The problem is that sometimes the display loads before FTV can actually update the value of the Memory Tag, even though I'm setting that tag value before I Load the Display. So I have to hold the Display inside the Load Event with a Timer. I can't use a while loop to check for tag state change because sometimes the tag updates first so there is no consistent event I can trap for. Sometimes the tag updates first and sometimes it doesn't and the only reliable method I've found to ensure the tag has updated is to give it a few seconds, then load the trend template and let it bail out of the Load Event.
My best guess is that FTV just has a sloppy implementation of VBA, it's certainly slow so I'm assuming it's just poorly integrated. But there has to be a better way to get that info to the display so it loads the right trend template on initialization. I know I could have multiple copies of the same display with the correct trend templates defined for each display but I don't want to use any more displays than necessary I usually push the limits on the licensed number of displays.
Is there a way to pass a Variable to the display that VBA can access or a way to pass a value directly to the ActiveX Trend from the calling function/control? The way I'm doing it works and I'm not looking for alternative work-arounds. I really just feel like my limited knowledge of FTV is the problem, I can't be the only one that does this with an HMI and there just has to be a clean way to do this.
I have a recurring issue with SE applications that use shared displays. I have a workaround but I'd really like to find a cleaner method.
Here's the layout.
I have an HMI that provides data on multiple identical systems. The main display provides an overview of all systems. From the main display the detail screens can be loaded for whichever system the user chooses. I use the same detail displays with tag place holders and load the displays with a parameter file for each system. This works well. However I have always have one or more detail displays that contain an ActiveX Trend object. I have Trend Templates setup for each system.
The problem is I haven't found a clean way to pass a variable to the display that it can use to load the correct trend template.
Here's what I've done in the past that I'm hoping to improve upon.
I define a Memory Type tag for System_number. From the button that loads the display I set the value of the memory tag first, then load the display with a /pParameter_File. Then in the Display_Load Event (VBA) I define taggroup and tag and assign the tag value to a VBA variable and then use the methods of the Trend ActiveX to load the trend template I want. Sounds like a Kludge Huh?
The problem is that sometimes the display loads before FTV can actually update the value of the Memory Tag, even though I'm setting that tag value before I Load the Display. So I have to hold the Display inside the Load Event with a Timer. I can't use a while loop to check for tag state change because sometimes the tag updates first so there is no consistent event I can trap for. Sometimes the tag updates first and sometimes it doesn't and the only reliable method I've found to ensure the tag has updated is to give it a few seconds, then load the trend template and let it bail out of the Load Event.
My best guess is that FTV just has a sloppy implementation of VBA, it's certainly slow so I'm assuming it's just poorly integrated. But there has to be a better way to get that info to the display so it loads the right trend template on initialization. I know I could have multiple copies of the same display with the correct trend templates defined for each display but I don't want to use any more displays than necessary I usually push the limits on the licensed number of displays.
Is there a way to pass a Variable to the display that VBA can access or a way to pass a value directly to the ActiveX Trend from the calling function/control? The way I'm doing it works and I'm not looking for alternative work-arounds. I really just feel like my limited knowledge of FTV is the problem, I can't be the only one that does this with an HMI and there just has to be a clean way to do this.
